Not exactly free, but Humble Bundle are
selling Kingdom Come: Deliverance along
with Treasures of the Past DLC; bundled
together for £31.99 (ON SALE for a limited time!)
a 20% reduction off the price of the Deluxe version._________________

I have a tip. The man from UNCLE. It is a great game with a unique setting in eastern Berlin. I really enjoy the game and recommend you play too. Something for the players of the Ikarus Mod. It is surprisingly for free, both for Android/iOS and for PC. The map of eastern Berlin is worth a visit, you can take a ride along the wall with a Volkspolizeiwagen, truck, fiat, or a legendary trabi. There are abandoned ruins (leftovers from the war), parks, checkpoints, narrow alleys - the map of the city is not boring, though a bit small. You have there some missions and you can even play multiplayer.

According to the comments and reviews the driving experience used to be bad but now after a few updates it is totally fine.

Here is the game (note that you need to have Unity Web Plugin installed, it doesn't load in Chrome and in some other web browsers , I use Internet Explorer to run it) http://www.manfromunclegame.com/